Casual sex and sex while drunk or high was more common among bullies and bully-victims than among other teens, a survey of more than 8,600 high school students found. Bully-victims are children who are both bullies and bullied.

"The time has come to acknowledge that bullying is a recognized health issue and that methods of prevention and help for those involved are important and necessary," said Dr. Jefry Biehler, chair of pediatrics at Miami Children's Hospital.

"Risk-taking behaviors among adolescents can and do have potential life-long consequences for the child and society," said Biehler, who was not involved in the study.

Programs aimed at preventing bullying and reducing unhealthy sexual practices should address the potential link between bullying and sexual risk-taking, the researchers suggested. However, the study does not prove that bullying causes teens to engage in risky sex.

"Findings from this study add to our understanding of the ways in which bullying affects youth and provide preliminary evidence that bullies and bullies who are also victims might be at heightened risk for sexual risk-taking behaviors," said lead researcher Melissa Holt, an assistant professor of counseling and human development at Boston University.

Because these risky sexual behaviors were seen mostly among heterosexual teens, Holt said the findings might be less applicable to gay or lesbian adolescents.

Also, Holt said, students who were solely victims of bullying weren't at "increased risk for sexual risk-taking."

"It may be that bullying and sexual risk reflect a coping response to stressors not captured in the study, such as harsh parenting," she said.

The increased risk for sexual risk-taking among bullies and bully-victims held even after taking into account factors such as dating violence, physical abuse and sexual abuse, Holt added.

Adolescence is a time when risk-taking is a concern, another expert noted. "We know that frontal lobes are still developing and judgment is not well-formed," said Dr. Victor Fornari, director of the division of child and adolescent psychiatry at North Shore-LIJ Health System in New Hyde Park, N.Y.

"Teens who are bullies may resort to higher-risk behavior, including higher-risk sexual behavior," he said.

"Bullying has all kinds of consequences," Fornari added. "This is one more negative consequence."

For the study, Holt's team reviewed answers provided by 8,687 teens who attend a Midwestern high school.

If they had ever had sex with someone they had just met or didn't know, the teens were considered to have engaged in casual sex. Similarly, if they had ever had sex while under the influence of alcohol, marijuana or other drugs, they were categorized as having sex under the influence.

Overall, about 6 percent of respondents admitted to being a bully, and 6 percent said they were bully-victims. Nine percent said they were victims of bullying.

Asked about sexual risk-taking, about one in four teen bullies and nearly one in five bully-victims had engaged in casual sex, the study found. By comparison, only 8 percent of victims and roughly 7 percent of teens not involved in bullying had had casual sex.

Having sex while drunk or high was reported by 34 percent of bullies and 23 percent of bully-victims, but only 11 percent of victims and 12 percent of teens who had no experience with bullies, the investigators found.